Inductive displacement transducer using plural magnetic screens rotatable about different axis to modify an inductance proportional to the displacement

Abstract

An inductive transducer intended, according to the invention, for converting the displacement of mechanical objects into an electric signal, comprising primary and secondary coils with cores, connected to one of mutually moving mechanical objects. The coils are arranged one opposite the other with a gap, wherein a main screen connected to the other moving object and at least one auxiliary screen are located. The auxiliary screen is set movably in a plane parallel to the main screen. The inductive transducer of this invention permits obtaining a functional relationship between the output signal and two or more displacements of mechanical objects, and thereby enables the relationship, including the slope thereof, to be controlled by simple means.

What is claimed is: 
     
       1. An inductive transducer for converting displacements of at least two mutually moving mechanical objects into electric signals, comprising: (a) first and second ferromagnetic cores operatively associated with said at least two mutually moving objects;   (b) a primary coil associated with said first core and a secondary coil associated with said second core, said primary and said secondary coils and said first and said second cores being spaced from one another and separated from each other by a gap, said first and said second cores being positioned in face to face relationship with each other on opposite sides of said gap;   (c) a first plate screen movable about a first axis and coupled for movement with one of said mutually moving mechanical objects and between said primary and secondary coils within said gap, said screen screening magnetic flux between said coils;   (d) at least one additional plate screen movable about a second axis spaced from said first axis and associated with another of said mutually moving mechanical objects and arranged in said gap also to screen magnetic flux between said coils, said first plate screen being movable in a plane parallel to said additional plate screen, and said first plate screen and said additional screen constituting together a common screening surface for said primary and said secondary cores, and   (e) said primary coil being connected to a source of energy, said secondary coil producing electrical signals in response to energization of said primary coil by said source of energy, said first plate screen causing a variation depending on its position in said gap in the electrical signals produced by said secondary coil, and said additional plate screen also causing a variation in the electrical signals produced by said secondary coil depending upon the position of said additional plate screen in said gap, said additional plate screen being used together with said first plate screen to provide for a predetermined functional relationship between said electric signals and mutual displacement of said mechanical objects.   
     
     
       2. An inductive transducer as claimed in claim 1, wherein at least one said additional plate screen has a shape different from that of said first plate screen. 
     
     
       3. An inductive transducer as claimed in claim 1, wherein said first plate screen and at least one said additional plate screens are made in the form of superimposed plates adapted to be moved and to be locked relative to each other. 
     
     
       4. An inductive transducer as claimed in claim 1, wherein: said first ferromagnetic core includes a first primary core member having a first primary coil member and a second primary core member having a second primary coil member, said second ferromagnetic core includes a first secondary core member having a first secondary coil member and a second secondary core member having a second secondary coil member positioned for cooperation with said first primary coil member and said second primary coil member, respectively, and separated from each other to provide said gap between said first primary coil member and first secondary coil member, and said second primary coil member and said second secondary coil member;   said ferromagnetic cores are linked with a third one of said mutually moving mechanical objects,   said first plate screen and said at least one of said additional plate screens are made in the form of partially superimposed plates adapted to be moved in directions opposite to each other in an overlapped relationship,   said first plate screen is movable in said gap between said first primary coil member and said first secondary coil member, and said one additional plate screen is movable in said gap between said second primary coil member and said second secondary coil member and in partial overlapping relationship with said first plate screen.   
     
     
       5. An inductive transducer as claimed in claim 1, wherein: said first plate screen and at least one of said additional plate screens are linked with each other and with one of said mutually moving mechanical objects.   
     
     
       6. An inductive transducer as claimed in claim 4, wherein: at least one of said additional plate screens has a shape different from that of said first plate screen,   said first plate screen and said differently shaped one of said additional plate screens are made in the form of superimposed plates adapted to be moved and to be locked relative to each other, and   locking means including a guide and a preset locking device to lock said first plate screen and said differently shaped additional plate screen together to form a composite screen which can be moved by one of said other of said mutually moving mechanical objects and said respective one of said mutually moving mechanical objects.   
     
     
       7. An inductive transducer as claimed in claim 5, wherein at least one of said additional plate screens has a shape different from that of said first plate screen. 
     
     
       8. An inductive transducer as claimed in claim 5, wherein said first plate screen and at least one of said additional plate screens are made in the form of superimposed plates adapted to be moved and to be locked relative to each other. 
     
     
       9. An inductive transducer as claimed in claim 5, including: gearing linking said first plate screen and at least one said additional plate screens for relative movement with respect to each other and with respect to said first and said second coils,   said gearing rotating said screens in a direction opposite to each other and about said first and said second axes.